Dark Chocolate And Autoimmune Hepatitis Why Is Dark Chocolate In The Main Display When Buying Chocolate?

Why is Dark chocolate in the main display when buying chocolate? - dark chocolate and autoimmune hepatitis

When I look for chocolate at Wal * Mart has a bunch of chocolate available and was the main product in the cap. I had to search to find the chocolate milk. Why is easier to find dark chocolate than milk chocolate?
Is it like Diet Coke is easier to achieve than regular Coke?